在 LangGraph 中集成 Mem0 记忆系统教程

简介

LangGraph 是一个强大的对话流程编排框架，而 Mem0 则是一个高效的记忆系统。本教程将介绍如何将两者结合，创建一个具有记忆能力的客服助手系统。

环境准备

首先安装必要的依赖：

pip install langgraph mem0 langchain openai

基础配置

1. 导入必要的模块

from openai import OpenAI
from mem0 import Memory
from mem0.configs.base import MemoryConfig
from mem0.embeddings.configs import EmbedderConfig
from mem0.llms.configs import LlmConfig
from typing import Annotated, TypedDict, List
from langgraph.graph import StateGraph, START
from langgraph.graph.message import add_messages
from langchain_openai import ChatOpenAI
from langchain_core.messages import SystemMessage, HumanMessage, AIMessage

2. 配置基础参数

# 集中管理配置
API_KEY = "your-api-key"
BASE_URL = "your-base-url"# 配置 LLM
llm = ChatOpenAI(temperature=0,openai_api_key=API_KEY,openai_api_base=BASE_URL,model="qwen-turbo"
)# 配置 Mem0
config = MemoryConfig(llm = LlmConfig(provider="openai",config={"model": "qwen-turbo","api_key": API_KEY,"openai_base_url": BASE_URL}),embedder = EmbedderConfig(provider="openai",config={"embedding_dims": 1536,"model": "text-embedding-v2","api_key": API_KEY,"openai_base_url": BASE_URL})
)

核心概念解析

1. 状态定义

在 LangGraph 中，我们需要定义对话状态：

class State(TypedDict):messages: Annotated[List[HumanMessage | AIMessage], add_messages]mem0_user_id: str

这个状态包含：

messages：当前对话的消息列表
mem0_user_id：用户标识，用于 Mem0 记忆检索

2. 对话节点实现

def chatbot(state: State):messages = state["messages"]user_id = state["mem0_user_id"]# 检索相关记忆memories = mem0.search(messages[-1].content, user_id=user_id)context = "\n".join([f"- {memory['memory']}" for memory in memories["results"]])# 构建系统提示system_prompt = f"""You are a helpful customer support assistant. Use the provided context to personalize your responses and remember user preferences and past interactions.
Relevant information from previous conversations:
{context}"""# 生成回复并存储记忆response = llm.invoke([SystemMessage(content=system_prompt)] + messages)mem0.add(f"User: {messages[-1].content}\nAssistant: {response.content}", user_id=user_id)return {"messages": [response]}

3. 图结构构建

graph = StateGraph(State)
graph.add_node("chatbot", chatbot)
graph.add_edge(START, "chatbot")
graph.add_edge("chatbot", "chatbot")
compiled_graph = graph.compile()

工作流程解析

状态初始化：
- 创建初始状态，包含用户消息和用户ID
- 状态通过图结构传递给对话节点
记忆检索：
- 使用 Mem0 的 search 方法检索相关历史记忆
- 根据语义相似度返回最相关的记忆
上下文整合：
- 将检索到的记忆整合到系统提示中
- 确保 AI 能够理解历史上下文
响应生成：
- 使用 LLM 生成回复
- 将新的对话内容存储到 Mem0 中

运行对话

def run_conversation(user_input: str, mem0_user_id: str):config = {"configurable": {"thread_id": mem0_user_id}}state = {"messages": [HumanMessage(content=user_input)], "mem0_user_id": mem0_user_id}for event in compiled_graph.stream(state, config):for value in event.values():if value.get("messages"):print("Customer Support:", value["messages"][-1].content)return

主程序示例

if __name__ == "__main__":mem0_user_id = "customer_123"print("Welcome to Customer Support! How can I assist you today?")while (user_input := input("You: ").lower()) not in ['quit', 'exit', 'bye']:run_conversation(user_input, mem0_user_id)

关键特性

状态管理：
- LangGraph 提供了清晰的状态管理机制
- 支持复杂的对话流程控制
记忆检索：
- Mem0 提供语义化的记忆检索
- 支持多用户隔离
流程编排：
- 通过图结构定义对话流程
- 支持灵活的节点扩展

完整代码与示例

from openai import OpenAI
from mem0 import Memory
from mem0.configs.base import MemoryConfig
from mem0.embeddings.configs import EmbedderConfig
from mem0.llms.configs import LlmConfigfrom langchain_openai import ChatOpenAI
from langchain_core.messages import SystemMessage, HumanMessage, AIMessage
from langchain_core.prompts import ChatPromptTemplate, MessagesPlaceholder
from typing import List, DictAPI_KEY = "your api key"
BASE_URL = "https://dashscope.aliyuncs.com/compatible-mode/v1"openai_client = OpenAI(api_key=API_KEY,base_url=BASE_URL,
)llm = ChatOpenAI(temperature=0,openai_api_key=API_KEY,openai_api_base=BASE_URL,model="qwen-turbo"
)config = MemoryConfig(llm = LlmConfig(provider="openai",config={"model": "qwen-turbo","api_key": API_KEY,"openai_base_url": BASE_URL}),embedder = EmbedderConfig(provider="openai",config={"embedding_dims": 1536,"model": "text-embedding-v2","api_key": API_KEY,"openai_base_url": BASE_URL})
)mem0 = Memory(config=config)prompt = ChatPromptTemplate.from_messages([SystemMessage(content="""You are a helpful travel agent AI. Use the provided context to personalize your responses and remember user preferences and past interactions. Provide travel recommendations, itinerary suggestions, and answer questions about destinations. If you don't have specific information, you can make general suggestions based on common travel knowledge."""),MessagesPlaceholder(variable_name="context"),HumanMessage(content="{input}")
])def retrieve_context(query: str, user_id: str) -> List[Dict]:"""Retrieve relevant context from Mem0"""memories = mem0.search(query, user_id=user_id)seralized_memories = ' '.join([mem["memory"] for mem in memories["results"]])context = [{"role": "system", "content": f"Relevant information: {seralized_memories}"},{"role": "user","content": query}]return contextdef generate_response(input: str, context: List[Dict]) -> str:"""Generate a response using the language model"""chain = prompt | llmresponse = chain.invoke({"context": context,"input": input})return response.contentdef save_interaction(user_id: str, user_input: str, assistant_response: str):"""Save the interaction to Mem0"""interaction = [{"role": "user","content": user_input},{"role": "assistant","content": assistant_response}]mem0.add(interaction, user_id=user_id)def chat_turn(user_input: str, user_id: str) -> str:# Retrieve contextcontext = retrieve_context(user_input, user_id)# Generate responseresponse = generate_response(user_input, context)# Save interactionsave_interaction(user_id, user_input, response)return responseif __name__ == "__main__":print("Welcome to your personal Travel Agent Planner! How can I assist you with your travel plans today?")user_id = "john"while True:user_input = input("You: ")if user_input.lower() in ['quit', 'exit', 'bye']:print("Travel Agent: Thank you for using our travel planning service. Have a great trip!")breakresponse = chat_turn(user_input, user_id)print(f"Travel Agent: {response}")